What are humectants primarily used for in skincare?

Humectants are primarily utilized in skincare for their ability to attract and retain moisture from the environment to the skin's surface. This characteristic aids in hydrating the skin, thereby improving its overall appearance and texture. Humectants work by pulling water into the outer layer of the skin, which helps maintain skin hydration levels and prevents dryness.

The other options focus on different functions unrelated to the primary role of humectants. For example, exfoliation addresses the removal of dead skin cells, which is a separate process typically achieved through physical scrubs or chemical exfoliants. Sun protection is provided by ingredients such as sunscreens, which contain specific compounds designed to absorb or reflect UV radiation. Reducing skin redness is typically associated with soothing agents or anti-inflammatory ingredients rather than humectants. Thus, the correct choice highlights the critical function of humectants in enhancing skin hydration.